U.S. patent number 8,522,614 [Application Number 12/787,464] was granted by the patent office on 2013-09-03 for in-line inspection methods and closed loop processes for the manufacture of prepregs and/or laminates comprising the same.
This patent grant is currently assigned to General Electric Company. The grantee listed for this patent is Waseem Ibrahim Faidi, Andrzej Michael May, Shu Ching Quek. Invention is credited to Waseem Ibrahim Faidi, Andrzej Michael May, Shu Ching Quek.
United States Patent |
8,522,614 |
May , et al. |
September 3, 2013 |
**Please see images for:
( Certificate of Correction ) ** |
In-line inspection methods and closed loop processes for the
manufacture of prepregs and/or laminates comprising the same
Abstract
In-line inspection methods are provided. The methods comprise
measuring at least two parameters/properties of a prepreg and/or
laminate during the manufacture thereof. In some embodiments, the
data collected using the inline inspection methods may be processed
and/or provided to a manual or automated controller, in order to
provide a closed loop method for the manufacture of the prepregs
and/or laminates. Apparatus for carrying out the methods are also
provided, as are articles comprising a prepreg and/or laminate made
using the apparatus.
Inventors: |
May; Andrzej Michael
(Schenectady, NY), Faidi; Waseem Ibrahim (Schenectady,
NY), Quek; Shu Ching (Clifton Park, NY) |
Applicant: |
Name |
City |
State |
Country |
Type |
May; Andrzej Michael
Faidi; Waseem Ibrahim
Quek; Shu Ching |
Schenectady
Schenectady
Clifton Park |
NY
NY
NY |
US
US
US |
|
|
Assignee: |
General Electric Company
(Niskayuna, NY)
|
Family
ID: |
44082313 |
Appl.
No.: |
12/787,464 |
Filed: |
May 26, 2010 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20110135872 A1 |
Jun 9, 2011 |
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Current U.S.
Class: |
73/570; 73/866.5;
73/583 |
Current CPC
Class: |
B32B
41/00 (20130101); G01N 29/04 (20130101); G01N
29/0663 (20130101); G01N 27/90 (20130101); G01N
2291/0231 (20130101); B32B 2305/076 (20130101); Y10T
428/24 (20150115) |
Current International
Class: |
G01H
9/00 (20060101) |
Field of
Search: |
;73/570,583,597,866.5
;428/98 ;156/157 ;264/407 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1046666 |
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Oct 2000 |
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EP |
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2007265863 |
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Oct 2007 |
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JP |
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2009063398 |
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May 2008 |
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WO |
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2008070705 |
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Jun 2008 |
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WO |
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Other References
Advanced forthe Topographic Characterization of SMC materials,
Calvimontes et al., 2009. cited by examiner .
Search Report from corresponding EP Application No. 11166987.5-2204
dated Sep. 21, 2011. cited by applicant.
|
Primary Examiner: Saint Surin; J M
Attorney, Agent or Firm: Agosti; Ann M.
Claims
What is claimed is:
1. An apparatus for the manufacture of a prepreg and/or laminate
comprising A resin infusion apparatus; A layup apparatus; An
optical metrology unit for measuring at least one first property of
the prepeg and/or the laminate, said at least one first property
including surface topography; An ultrasound probe for measuring at
least one second property of the prepeg and/or the laminate, said
at least one second property including porosity; A controller for
making adjustments in the operation of the resin infusion apparatus
and/or the layup apparatus based on the at least one first property
and the at least one second property; and A processor operatively
disposed relative to the optical metrology unit and the ultrasound
probe and the controller so that information may be transmitted
therebetween.
2. An article comprising a prepreg prepared using the apparatus of
claim 1.
3. The article of claim 2, comprising a turbine component.
4. The article of claim 3, wherein the turbine component comprises
a spar, spar cap, airfoil skin, or the cylindrical root section or
tower sections of a wind turbine.
5. The article of claim 2, comprising an aviation component.
6. The article of claim 5, wherein the aviation component comprises
a wing skin, fuselage skin, spar, or flat laminate.
7. A closed loop method for the manufacture of a prepreg and/or
laminate comprising: conducting a step of a prepreg and/or laminate
manufacturing process; measuring at least two properties of the
prepreg and/or laminate, said at least two properties including
surface topography and porosity; analyzing the measured at least
two properties; and adjusting the manufacturing process according
to the analysis of the measured at least two properties.
Description
FIELD
The embodiments disclosed relate generally to in-line inspection
methods and closed loop methods for the manufacture of prepregs
and/or laminates incorporating these.
BACKGROUND
Composite materials have been used to produce both lightly loaded
and highly loaded structures, useful in non-load carrying and load
carrying applications, respectively. Examples of the former include
boat hulls and automobile body panels, while examples of the latter
include pressure vessels, frames, fittings and aircraft fuselages.
Because of their wide applicability, composite materials have found
use in the automotive, marine and aerospace industries. However,
due to their ability to be manufactured in forms suitable for
bearing heavy loads, composite materials are particularly
ubiquitous in the design of load bearing structural members.
Composite materials typically include a fibrous material, such as
carbon, aramid, glass or quartz, bonded together with a resin
material, such as an epoxy. The load in such composite materials is
carried primarily by the fibrous material, and so, the load
carrying properties of the composite can be altered by altering the
orientation of the fibers in the composite material. For example,
composite materials with unidirectional fibers, such as tapes or
tows, may generally exhibit the strongest tensile strength along
the axis of the fibers. Woven fabrics and bi-directional mats are
typically strongest in the plane of the material. Thus, when
designing composite materials, fiber orientation and the number of
layers, also known as plies, is typically specified in
consideration of the anticipated load the composite item will
experience.
Fiber composite laminates or parts may typically be manufactured by
first impregnating the fiber reinforcement with resin to form a
prepreg, and then consolidating two or more layers of prepreg into
a laminate. Inherent in the layup process used to form such
materials are the formation of a variety of defects, including
wrinkles, voids, delaminations, and the like. For example, voids in
the prepreg and/or laminate, may result from the inefficient
penetration of the resin in to the fiber bundle, tow, or roving, or
from outgassing during the consolidation process. Such defects may
be formed in greater number when the composite article being formed
is relatively large, or incorporates a contour, or otherwise
complex shape.
Many times, such defects may not be on the surface or otherwise be
immediately detectable during the layup process, or, such defects
may become visible or exacerbated during the curing process. The
presence of such defects in the finished article can de-rate the
material strength up to a factor of 2, and so, may require that the
article be repaired, or, may even require that the part be
scrapped, thus contributing to an increase in manufacturing cost
due to either the repair cost and/or lead-time required to replace
scrapped articles.
Many inspection methods have been applied independently to
composite materials. However, the resolution of defects when using
some of these composite materials may limited in some applications.
For example, in composite materials wherein the fibers or tows have
a random orientation, or in composite materials wherein the fibers
desirably comprise carbon, either the structure or the carbon may
scatter the measured signal. Further, in many applications, it may
be desirable, or even necessary, to obtain multiple measurements,
including both measurements of physical parameters and material
properties, of the composite material. Many inspection apparatus'
are capable of providing only one measurement, or type of
measurement, or provide data with a standard deviation unacceptable
in some applications. And, equipment capable of conducting more
sophisticated measurements can be expensive and thus not
cost-effective in applications where the profit margin of the
article being manufactured does not warrant the expense.
It would therefore be desirable to develop new inspection methods
capable of being incorporated inline. Such methods would desirably
allow defects to be detected and compensated for during the
manufacture of composite materials, and as a result, reduce or
eliminate the amount of rework or scrap that can be produced by
conventional manufacturing processes.
BRIEF DESCRIPTION
There is provided an in-line inspection method comprising measuring
at least two parameters and/or properties of a prepreg and/or
laminate during the manufacture thereof.
In another aspect, there is provided a method for the manufacture
of a prepreg and/or laminate comprising conducting at least one
step of a prepreg and/or laminate manufacturing process and
measuring at least two properties of the prepreg and/or laminate
before, during or after the at least one step.
In another aspect, there is provided an apparatus for the
manufacture of a prepreg and/or laminate. The apparatus comprises a
controller, a resin infusion apparatus, at least one measurement
apparatus, and a processor. The processor is operatively disposed
relative to the measurement apparatus and controller so that
information may be transmitted therebetween. Articles prepared from
prepregs and/or laminates made using the apparatus are also
provided.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features, aspects, and advantages of the present
invention will become even better understood when the following
detailed description is read with reference to the accompanying
drawings in which like characters represent like parts throughout
the drawings, wherein:
FIG. 1 is a flow chart representing steps in an exemplary inline
inspection method in accordance with some embodiments;
FIG. 2 is a graphical depiction of optical metrology data obtained
from a prepreg according to one embodiment;
FIG. 3 is a graphical depiction of ultrasound data obtained from a
prepreg according to one embodiment; and
FIG. 4 is a flow chart representing steps in an exemplary inline
inspection method in accordance with some embodiments.
DETAILED DESCRIPTION
The above brief description sets forth features of the various
embodiments of the present invention in order that the detailed
description that follows may be better understood, and in order
that the present contributions to the art may be better
appreciated. There are, of course, other features of the invention
that will be described hereinafter and which will be for the
subject matter of the appended claims.
In this respect, before explaining several embodiments of the
invention in detail, it is understood that the various embodiments
of the invention are not limited in their application to the
details of the construction and to the arrangements of the
components set forth in the following description or illustrated in
the drawings. The invention is capable of other embodiments and of
being practiced and carried out in various ways. Also, it is to be
understood that the phraseology and terminology employed herein are
for the purpose of description and should not be regarded as
limiting.
The terms "first," "second," and the like, as used herein do not
denote any order, quantity, or importance, but rather are used to
distinguish one element from another. The terms "a" and "an" herein
do not denote a limitation of quantity, but rather denote the
presence of at least one of the referenced items. The modifier
"about" used in connection with a quantity is inclusive of the
stated value, and has the meaning dictated by context, (e.g.,
includes the degree of error associated with measurement of the
particular quantity). The suffix "(s)" as used herein is intended
to include both the singular and the plural of the term that it
modifies, thereby including one or more of that term.
Reference throughout the specification to "one embodiment" or "an
embodiment" means that a particular feature, structure, or
characteristic described in connection with an embodiment is
included in at least one embodiment. Thus, the appearance of the
phrases "in one embodiment" or "in an embodiment" in various places
throughout the specification is not necessarily referring to the
same embodiment. Further, the particular features, structures or
characteristics may be combined in any suitable manner in one or
more embodiments.
Embodiments of the subject matter disclosed relate generally to
in-line inspection methods. The methods comprise measuring at least
two parameters/properties of a prepreg and/or laminate during the
manufacture thereof. In some embodiments, the data collected in the
inline inspection methods may be processed and/or provided to a
manual or automated controller, in order to provide a closed loop
method for the manufacture of the prepregs and/or laminates.
Apparatus for carrying out the methods are also provided, as are
articles comprising a prepreg and/or laminate made using the
apparatus.
FIG. 1 is a flow chart illustrating one embodiment of the method.
As shown, method 100 involves manufacturing a prepreg and/or
laminate at step 102, and measuring at least two properties of the
prepreg and/or laminate during the manufacture thereof at step 104.
The measurements may generally be taken at any point in the
manufacturing process of a prepreg or laminate, such steps being
generally known to those of ordinary skill in the art, and
including, resin infusion, compression/compaction,
lamination/layup, consolidation and curing.
The properties and/or parameters measured can be any that provide
useful information about the prepreg and/or laminate. In some
embodiments, the measured properties and/or parameters provide
information related to the properties of the prepreg and/or
laminate, while in others, the measured properties and/or
parameters provide information related to defects, e.g., voids,
cracks, foreign inclusions, delaminations, porosity, wrinkles, or
fiber misalignment within the prepreg and/or laminate. Desirably,
at least two measurements are made so that more information is
obtained as compared to methods of inline inspection of prepregs
and/or laminates that utilize only one measurement.
In some embodiments, the at least two measurements may be the same
measurement, made at different stages of the manufacturing process,
while in others, the measurements may be different, and made at the
same, or different, stages of the manufacturing process. In certain
embodiments, one measurement may comprise one made substantially
at, or in relation to, the surface of the prepreg and/or laminate,
while the other measurement may be made below the surface, i.e., in
relation to the subsurface of the prepreg and/or laminate.
The particular method of measurement(s) will depend upon the
property(ies) desirably being measured. Measurement methods for
such properties are generally known, and include imaging
techniques, such as acoustic holography, optical metrology and many
varieties of cameras, e.g., microwave cameras, for dimensional
measurements, such as length, width, depth, or measurements made in
more than one dimension; thermometers or thermocouples for the
measurement of thermal conductivity; magnetometers such as
hall-effect sensors, giant magneto-resistive sensors, anisotropic
magneto-resistive sensors, atomic magnetometers, superconducting
quantum interference devices (SQUIDS) or eddy current coils for the
measurement of magnetic permeability; capacitive plates or
striplines for the measurement of dielectric constant; ohmmeters
and eddy current coils for the measurement of electric
conductivity; densitometers, ultrasound or x-ray for the
measurement of density or porosity; and magnetometers and coils for
the measurement of nuclear quadruple resonance frequency.
In some embodiments, at least one of the measurements provides
dimensional information, such as length, width, depth, or
measurements made in more than one dimension. Many imaging
techniques are available capable of providing such measurements,
either directly, or indirectly via an image that may be further
analyzed to provide the desired dimensional information. Examples
of such imaging techniques include acoustic holography, eddy
current array imaging, optical metrology and many varieties of
cameras, e.g., microwave cameras.
In some embodiments, optical metrology may be used, and is
advantageously capable of providing information related to wrinkles
or waviness present in the reinforcement material, prepreg and/or
laminate. Optical metrology data obtained from a prepreg according
to and/or prepared according to one embodiment is shown in FIG. 2,
wherein the peak indicates a wrinkle in the prepreg.
Techniques for conducting optical metrology measurements, as well
as analyzing the results thereof, are well known to those of
ordinary skill in the art, and are described generally in
Yoshizawa, Taoru, Handbook of optical metrology principals and
applications, Taylor & Francis, Boca Raton, co. 2008 hereby
incorporated by reference herein in its entirety. Further,
equipment for conducting such measurements is commercially
available from a variety of sources including General Electric
Company, FARO and Minolta.
In some embodiments, at least one of the measurements provides
information related to a property of the prepreg or laminate, or
the presence of a defect in the same. For example, at least one
measurement may desirably provide information related to the
thermal conductivity, magnetic permeability, dielectric constant,
electric conductivity, density, nuclear quadruple resonance
frequency, etc., of the prepreg and/or laminate. In some
embodiments, ultrasound measurements are employed and provide
information related to the porosity, fiber volume fraction, voids
and/delaminations of the prepreg and/or laminate. Ultrasound data
obtained from a prepreg according to and/or prepared according to
one embodiment is shown in FIG. 3.
Techniques for conducting ultrasound measurements, as well as
analyzing the results thereof, are well known to those of ordinary
skill in the art, and are described generally in Data, S. K. and
Shah, A. H., Elastic waves in composite media and structures with
applications to ultrasonic nondestructive evaluation, CRC Press,
Boca Raton, co. 2009, hereby incorporated by reference herein in
its entirety. Further, equipment for conducting such measurements
is commercially available from a variety of sources including
General Electric, Olympus, and NDT Systems.
Whatever the measurement method(s) utilized, appropriate sensors,
or arrays of sensors, therefore are desirably operatively disposed
relative to the prepreg and or laminate, or processing equipment
therefore at the point of the manufacturing process at which the
measurement information is desirably obtained. In some embodiments,
the sensor or array(s) of sensors may advantageously be placed
proximal to, distal to, or in close proximity to where the resin is
desirably infused into the reinforcement material, and/or
compaction/compression of the prepreg, layup of one or more
prepregs to provide the laminate, or consolidation of the laminate
takes place. Stated another way, at least one of the measurements
is taken before, during or after infusion of a resin onto a
reinforcement material, a compaction step, a lamination/layup step,
a consolidation step and/or a curing step.
In those embodiments wherein optical metrology is employed to
obtain one of the measurements, it may advantageously be employed
during layup, when it is expected to provide information related to
the laminate surface topography. In those embodiments wherein
ultrasound measurements are employed, they may advantageously be
taken during infusion, and/or prior to, or during compaction, when
they are expected to provide information related to the porosity of
the prepreg.
In some embodiments, the data obtained from at least one
measurement is advantageously used to monitor and/or modify the
manufacturing process. In other words, the data obtained from the
measurements may, in some embodiments, be provided to a processor
capable of manipulating the data. For example, the data may be
manipulated to provide a historical overview of the measured
property of the prepreg and/or laminate, or, the data may be
manipulated in order to predict how the properties and/or defects
within prepreg and/or laminate may develop during further
processing and/or storage.
Such an embodiment is shown in FIG. 4. As shown, method 400
comprises conducting a step of a prepreg/laminate manufacturing
process at step 404, measuring at least two properties of the
prepreg/laminate at step 406, and analyzing the data obtained at
step 408. The analysis of the data may then be utilized to adjust
the manufacturing process, if necessary or desired, as shown at
step 402.
In some embodiments, the data may be manipulated in order to
predict how defects in the uncured, or "green-state", prepreg
and/or laminate may present in the cured part. In the same, or
other embodiments, the data may be manipulated in order to
correlate any defects detected in the measuring steps to cured part
strength. In other words, the data may be manipulated in more than
one way, to provide more than one indication. In some embodiments,
for example, the data may be manipulated to provide both a
prediction of how defects in green-state parts will present in
cured parts, and what impact these defects will have in the cured
part strength.
Process modeling software and techniques are well known in the art,
and these may also be applied to the data obtained during practice
of the methods to predict, e.g., defects that may remain, or be
exacerbated in a cured part from green state indications, and the
impact any such defects may have on the cured part strength. For
example, suitable methods for conducting such analysis are
described, for example, in Sridhar Ranganathan, Suresh G. Advani,
and Mark A. Lamontia, "A Non-Isothermal Process Model for
Consolidation and Void Reduction during In-Situ Tow Placement of
Thermoplastic Composites," Journal of Composite Materials, 1995
vol. 29, pp. 1040-1062; Yerramalli, C. S., Waas, A. M., "A
nondimensional number to classify composite compressive failure,"
Journal of Applied Mechanics, Transactions ASME, 2004, vol. 71, no.
3, pp. 402-408 and Yerramalli, C. S., Waas, A. M., "A failure
criterion for fiber reinforced polymer composites under combined
compression-torsion loading", International Journal of Solids and
Structures, 2003, vol. 40, no. 5, pp. 1139-1164, hereby
incorporated herein by reference for any and all purposes.
Such analysis can be used, in some embodiments, to make changes to
the process in order to minimize, or even eliminate, defect
formation. Such embodiments thus provide the advantage of a
reduction in reworking, or scrap, of defective articles made by the
process. Such process modifications may either be made manually, or
via an automated controller operatively disposed relative to the
processor in order to receive information therefrom, and relative
to the prepreg and/or layup apparatus, in order to provide
information thereto.
The present methods are advantageously and readily incorporated
into any apparatus for the manufacture of a prepreg and/or
laminate, and so, such apparatus are also provided herein.
Generally speaking, the apparatus comprises a controller, a resin
infusion apparatus, at least one measurement apparatus, and a
processor. The processor is operatively disposed relative to the
measurement apparatus and controller so that information may be
transmitted therebetween. In some embodiments, the apparatus may
also comprise a layup apparatus.
The at least one measurement apparatus may be positioned at any
location wherein data related to the prepreg and/or laminate can
be, and is desirably, collected. In some embodiments, the same type
of measurement apparatus may be used at more than one location,
while in the same, or in other, embodiments, at least two
measurement apparatus are utilized. The measurement apparatus will
depend upon the data desirably obtained, and can be chosen based
upon the same. In some embodiments, an optical metrology unit is
utilized, either alone or in combination with an ultrasound
measurement device.
For example, in those embodiments, wherein at least one measurement
provides dimensional data, and the measurement is taken with one or
more optical metrology device, the device(s) may be positioned,
e.g., in close proximity to the layup head, and where it will
generate 2-D images of the laminate surface topography that, in
turn, can be analyzed to detect and characterize any wrinkles in
the surface of the laminate, e.g., as shown in FIG. 2. In those
embodiments wherein ultrasound measurements are desirably taken,
the ultrasound probe(s) may be placed in close proximity to the
resin infusion stage and/or the compression/compaction stage, where
it will collect data that can be used to generate graphs such as
that shown in FIG. 3, indicative of the porosity of the
prepreg/laminate at a given depth.
The data is then processed by the processor to provide data, e.g.,
indicative of the effect of any defects in the green state prepreg
and/or laminate on the number and severity of defects the
corresponding cured part and/or the impact of any such defects on
cured part strength. The processed data provided to the controller,
which may then adjust parameters of the process, if desired or
required, to reduce the amount, or magnitude, of defects generated
in the prepreg and/or laminate by the process.
Process adjustments that may impact the presence, number or impact
of defects in the green state prepreg and/or laminate include, but
are not limited to, tow tension, temperatures, layup speed, roller
pressure, and resin content. And, the processed data may indicate,
and so the controller may adjust any of these manually or
automatically. Automatic control may be advantageous in some
embodiments, as it provides the opportunity for a closed-loop
process.
The present methods and apparatus may be utilized in connection
with the manufacture of any prepreg and/or laminate, regardless of
the composition thereof. Prepregs typically comprise one or more
curable resins, and one or more reinforcing materials, while
laminates typically comprise multiple prepregs, layered one upon
another.
Generally speaking, suitable curable resins for use in prepregs and
laminates include thermoplastic polymeric compositions such as
polystyrene, polyethylene terephthalate, polymethylmethacrylate,
polyethylene, polypropylene, polyvinylacetate, polyamide, polyvinyl
chloride, polyacrylonitrile, polyesters, polyvinyl chloride,
polyethylene naphthalate, polyether ketone, polysulfone,
polycarbonate, and copolymers thereof.
Prepregs and laminates may also utilize thermoset resins, suitable
examples of which include, but are not limited to epoxies,
polyesters, vinylesters, phenolic resins, polyurethanes,
polyamides, or combinations of two or more of these. Adhesive
compositions particularly well suited for use in the present
invention include crosslinked thermosetting systems such as
polyesters, vinyl-esters epoxies (including acid, base and addition
cured epoxies), polyurethanes, silicone resins, acrylate polymers,
polysiloxanes, polyorganosiloxanes, and phenolics, as well as
blends or hybrids of any of these.
Structural adhesives are often used in prepregs and laminates, and
may be used in the prepregs and laminates prepared by the present
methods and/or apparatus. Preferred structural adhesives for use in
the present composite systems include polyesters, methyl
methacrylates, and the like.
Any suitable reinforcing material may be infused using the
apparatus, systems and methods described. For example, relatively
continuous fibers, or tows, may be arranged to form a
unidirectional array of fibers, a cross-plied array of fibers, or
bundled in tows that are arranged to form a unidirectional array of
tows, or that are woven or cross-plied to form a two-dimensional
array, or that are woven or braided to form a three-dimensional
fabric. For three-dimensional fabrics, sets of unidirectional tows
may, for example, be interwoven transverse to each other.
Useful fibers to be included in such reinforcing materials, such as
tapes or fabrics, include without limitation, glass fibers, carbon
and graphite fibers, basalt fibers, polymeric fibers, including
aramid fibers, boron filaments, ceramic fibers, metal fibers,
asbestos fibers, beryllium fibers, silica fibers, silicon carbide
fibers, and the like. The fibers may be non-conductive or
conductive, depending upon the desired application of the
prepreg.
The present methods may be applied in the manufacture of any
article comprising a prepreg and/or laminate and are particularly
advantageous when applied to large articles due to the cost
associated with the manufacture of such articles, and thus, the
cost of reworking or scrapping the same. The present methods may
also provide particular benefit when applied to prepregs, laminates
and/or articles comprising these wherein the reinforcement material
comprises carbon filaments or fibers. Carbon has a significantly
higher stiffness and lower mass than many other reinforcement
materials, e.g., glass composites. Thus, its use as a reinforcement
material can enable the manufacture of prepregs, laminates and
articles that may be larger, and yet lighter, with yet acceptable
strength for the desired application. However, the final strength
of components made of prepregs and/or laminates comprising carbon
can depend greatly on the manufacturing process. Defects such as
wrinkles, delaminations, porosity and voids can greatly reduce the
final strength of the composite by introducing stress concentrators
into the material structure that may cause localized premature
failure or redirect stresses from applied loads in ways that are
not accounted for in the design of the component.
Examples of industries wherein large scale articles are routinely
manufactured from prepregs and/or laminates, and/or prepregs and/or
laminates comprising a carbon containing reinforcement material
include the energy industry, where large segments of, e.g.,
pipeline or other plant apparatus, may find benefit from
application of the principles discussed herein. Examples of
particular applications further include wind turbine components,
such as, turbine blades or subcomponents of such, e.g. spars, spar
caps, airfoil skins, or the cylindrical root section or tower
sections of wind turbines. Laminates prepared from prepregs
prepared using the methods and apparatus described may also be used
in aviation applications, such as wing skins, fuselage skins,
spars, or flat laminates such as ribs.
Those skilled in the art will appreciate that the conception, upon
which the disclosure is based, may readily be utilized as a basis
for designing other structures, methods, and/or systems for
carrying out the several purposes of the present invention. It is
important, therefore, that the claims be regarded as including such
equivalent constructions insofar as they do not depart from the
spirit and scope of the present invention.
While the disclosed embodiments of the subject matter described
herein have been shown in the drawings and fully described above
with particularity and detail in connection with several exemplary
embodiments, it will be apparent to those of ordinary skill in the
art that many modifications, changes, and omissions are possible
without materially departing from the novel teachings, the
principles and concepts set forth herein, and advantages of the
subject matter recited in the appended claims. Hence, the proper
scope of the disclosed innovations should be determined only by the
broadest interpretation of the appended claims so as to encompass
all such modifications, changes, and omissions. In addition, the
order or sequence of any process or method steps may be varied or
re-sequenced according to alternative embodiments.
* * * * *